Sewing machine hook and bobbin race assembly



Dec. 11, 1956 H, RABEZZANA 2,773,464

SEWING MACHINE HOOK AND BOBBIN RACE ASSEMBLY Filed Sept. 28, 1955 2 Sheets-Sheet 1 Dec. 11, 1956 H. RABEZZANA 2,773,464

SEWING MACHINE HOOK AND BOB BIN RACE ASSEMBLY Filed Sept. 28, 1953 l 2 Sheets-Sheet 2 2p IN V EN TOR.

#62 2 2/ FQZeZZd/Yd United States Patent SEWING MACHINE HOOK AND BOBBIN RACE ASSEMBLY Hector Rabezzana, Fen'ton, Mich. Application September 28, 1953, Serial No. 382,656 3 Claims. '(Cl. '112228) operations required in the manufacture of the hook.

A further object of the invention is to provide an improved fabricated sewing machine hook formed in two primary parts having cooperating portions defining a raceway in which the bobbin raceis mounted for rotary 'move ment' relative to the hook and is securely held in :assembled relation to the hook when the parts of the hook are secured in assembled relation.

It is also an object of the present invention to provide -:'an improved sewing machine hook adapted to be secured ito a'shaft for driving the hook and which provides the complete support for the bobbin race andsecu'rely holds the bobbin race against axial movement relative to the hook.

Another object bfthe present invention is to provide an improved sewing machine hook of the above mentioned type and including improved means for interconnecting and accuratelypositioning'the respective parts 'of the sewing machine hook relative to each other.

Other and more-detailed objects of the present invention will be appreciated from a consideration of the following specification, the appended claims and the accompanying drawings wherein:

Figure 1 is an 'endelevati'onal view-of a sewing machine hook and bobbin race assembly and showing a bobbin in place in the 'bobbin'race;

Figure '2 is a sectional'view of the structure illustrated in Figure 1, taken substantially along the 'line 2--2 thereof;

Figure 3 is a sectional view of the structure illustrated in Figure 2, taken substantially along the .line 33 thereof;

Figure 4 is a sectional view similar to Figure 3 showing parts removed and showing the relative rotary position to which the hook parts aremoved as an incident to dissassembly of the hook;

Figure 5 is an exploded 'elevational view of .thehook;

Figure '6 is an end elevational view of one of the hook parts;

Figures 7 and 8 are sectional views of the structure illustrated in Figure 6, taken substantially along the lines 7-7 and 88 thereof;

Figure 9 is an elevational view of another part of the hook; and,

Figures 10 and 11 are broken sectional views of the 2,773,464 Patented Dec. 11, 1956 structure illustrated in Figure 9, taken substantially along the lines 1010 and 1111.

Referring to the drawings, the present applicants improved hook and bobbin race assembly comprises a hook generally indicated at 20 adapted to be secured to a shaft 22 for rotary movement therewith and a bobbin race member 24 adapted to releasably support a bobbin 26. The improved hook 20 of the present invention comprises a hub member 28 having a cylindrical hub portion 30 adapted to be received on the end of a shaft 22 and secured thereto by any suitable means such, for example, as the set screw 32 illustrated in Figure 5. The hub member 28 has a generally radially outwardly extending flange 34 having a portion cut away as indicated at 36 in Figure 9 to prevent interference with the thread during the stitch forming operation. The flange 34 is disposed at one end of the cylindrical hub portion 30.

The outer face of the flange 34, or the left-hand face thereof, as viewed in Figure 2, has an enlarged shallow centrally disposed recess 38 which extends radially outwardly to .a point a short distance from the radially outer edge of the flange, leaving a flat annular bearing surface 40 disposed in a plane at right angles to the axis of the hub portion 36. This surface 40 defines a part of the raceway in which the bobbin race 24 is supported as hereinafter described.

The hook 243 also includes a generally C-shaped hook member 42 illustrated in Figure 6 which is generally annular in shape, including a hook point 44 adapted to pass,'in the usual manner, through the loop of the upper thread carried by the needle during the stitch forming operation, and having a tail portion 46 from which the loop is shed as the formation of the stitch approaches completion. The generally annular hook member 42 is interrupted between the point 44 and tail 46 to provide an opening 48 through which the thread moves during thereto and the'bearing surfaces 54 and 40 engage the opposite sides of the bobbin race flange 3410 prevent movement of the bobbin race 24 axially relative to the hook 20.

In the preferred embodiment illustrated, the hub member 28 and the hook member 42 are interconnected by means of an interrupted screw type connection. More specifically, the outer edge of the hub flange 34 includes spaced conical portions '56 and 58 and intermediate cylindrical portions 60 and 62;. These cylindricalportions are disposed at a radius less than generally the maximum radius of said conical portions. The-hook member 42 adjacent the cylindrical surface 52 and in axially opposed relation to the radiallyinwardly extending shoulder 54 is provided with a cylindrical portion 64 having a circumferential extent'slightlygreater than that of the conical portion 58 of the flange 34, and a surface 56 when the parts are in the finally assembled position shown in Figure 3.

The hub member 42 also has similarly undercut portions 70 and 72 adjacent the tail 46 and the hook point portion 44 to provide conical surfaces which co-operate respectively with the conical surface 56 and the conical surface 58 of the hub flange 34 when the parts are in the assembled position illustrated in Figure 3.

The members 28 and 42 are provided with recesses 74 and 76 adapted to be aligned when the parts are in assembled position and receive a locking key '78 which may be removably secured in position by a screw 80. In assembling the hook parts 28 and 42, the parts are tipped slightly relative to each other so that a portion of the conical portion 56 of the hub member flange 34 may be disposed under the undercut portion 70 provided adjacent the tail 46, while the edge portion of the flange 34 having the conical surface 58 thereon, is aligned with the portion of the hook member 42 provided with the cylindrical wall 64. With the parts thus aligned the parts may be tilted into coaxial position moving the conical surface 58 along the cylindrical surface 64 until the bearing surface 40 on the outer face of the flange 34 engages a co-operating shoulder 82 provided on the hook member 42 at the opposite end of the cylindrical surface 52 from the shoulder 54 and extending radially outwardly from the cylindrical surface 52. With the parts in this position, which is illustrated in Figure 4, the hub member 28 may be rotated in a counterclockwise direction relative to the hook member 42 as viewed in Figures 3 and 4, to the position illustrated in Figure 3. The parts are then locked in this relative rotative position by inserting the key 78 and securing it in place by means of the screw 80.

As is best illustrated in Figure 2, the bobbin race 24 is so shaped that its only contact with the hook 20 is through the bobbin race flange 50 which rotatably fits within the cylindrical surface 52 and is supported against axial movement by the shoulder 54 of the hook element 42 and the surface 40 of the hub member 28.

From a consideration of the above described construction it will be appreciated that the bobbin race 24 is completely supported Within the hook 20 and with the single exception of the opening 48 in the hook member 42, and the cutaway portion 36 of the flange 34, which are disposed in aligned relation when the parts are in the assembled position illustrated in Figure 3, the bearing surface 54 on the hook member 42 and the bearing surface 40 on the flange 34 co-operate to provide continuous bearings with the opposite sides of the bobbin race flange 50.

It will be appreciated, of course, that the bobbin race member 24 is placed in assembled relation with the hook member 42 prior to the assembly of the hub member 28 with the hook member 42 and upon completion of the assembly of the members 28 and 42, as above described, the bobbin race is engaged only at its flange 50 and is securely held in assembled position, and only rotative movement of the hook relative to the bobbin race 24 is permitted. In accordance with conventional practice, the bobbin race 24 is held against rotary movement relative to the sewing machine frame by means (not shown) which engages the upwardly extending finger 84 provided on the bobbin race 24.

While only one specific embodiment of the invention has been illustrated and described in detail herein, it will be readily appreciated by those skilled in the art that numerous modifications and changes may be made without departing from the spirit of the invention.

What is claimed is:

l. A rotary type hook assembly for a sewing machine, said hook assembly comprising a bobbin case having an annular flange, a hub member adapted to be secured to a rotary driving shaft, a hook member mounted on said hub member, said hub member and said hook member. having co-operating surfaces engaging said flange to support said bobbin case and defining a race for said flange, circumferentially spaced radially extending projections on one of said members, co-operating circumferentially spaced locking surfaces on the other of said members, said members being rotatable relative to each other between a locked position in which said projections engage said co-operating locking surfaces to prevent relative axial movement of said members and an unlocked position in which said projections are disengaged from said locking surfaces and in which said members may be moved axially apart, and key means mounted on and interconnecting said members to hold said members in said locked position.

2. A rotary type hook assembly for a sewing machine, said hook assembly comprising a bobbin case having an annular flange, a hub member adapted to be secured to a rotary driving shaft, a hook member mounted on said hub member, said hub member and said hook member having co-operating surfaces engaging said flange to support said bobbin case and defining a race for said flange, an interrupted screw on one of said members, a co-operating nut formed on the other of said members, said members being rotatable relative to each other between a locked position in which said interrupted screw engages said nut to prevent relative axial movement of said members and an unlocked position in which said interrupted screw is disengaged from said nut and in which said members may be moved axially apart, and key means mounted on and interconnecting said members to hold said members in said locked position.

3. A rotary type hook assembly for a sewing machine, said hook assembly comprising a bobbin case having an annular flange, a hub member adapted to be secured to a rotary driving shaft, a hook member mounted on said hub member, said hub member and said hook member having co-operating surfaces engaging said flange to support said bobbin and defining a race for said flange, said hub member having a radially outwardly extending flange having circumferentially spaced conically shaped edge portions and intermediate cylindrical portions, the maximum radius of said conical edge portions being greater than the radius of said intermediate cylindrical portions, said hook member being movable relative to said hub member between a locked position and an unlocked position and having circumferentially spaced undercut portions engaging said conical edge portions of said flange when said hook member is in said locked position, and key means mounted on and interconnecting said members to hold said hook member in said locked position, said hook member also having cylindrical portions intermediate said undercut portions through which said conically shaped edge portions of said flange of said hub member may be moved when said hook member is in said unlocked position.

References Cited in the file of this patent UNITED STATES PATENTS 1,387,144 Flanagan Aug. 9, 1921 2,218,556 Rubel Oct. 22, 1940 2,332,964 Colegrove Oct. 26, 1943 a I: v 

